add typescript

Kent C. Dodds · Kent C. Dodds · commit a5d2d971dd72 · 2019-08-14T11:59:13.000-06:00
diff --git a/.eslintrc b/.eslintrc
@@ -1,12 +1,21 @@
 {
+  "parser": "@typescript-eslint/parser",
   "parserOptions": {
     "ecmaVersion": 2019,
     "sourceType": "module",
     "ecmaFeatures": {
       "jsx": true
-    }
+    },
+    "project": "./tsconfig.json"
   },
-  "extends": ["eslint:recommended", "eslint-config-prettier"],
+  "plugins": ["@typescript-eslint/eslint-plugin"],
+  "extends": [
+    "eslint:recommended",
+    "plugin:@typescript-eslint/eslint-recommended",
+    "plugin:@typescript-eslint/recommended",
+    "eslint-config-prettier",
+    "eslint-config-prettier/@typescript-eslint"
+  ],
   "rules": {
     "strict": ["error", "never"]
   },
diff --git a/package-lock.json b/package-lock.json
diff --git a/package.json b/package.json
@@ -5,18 +5,22 @@
   "license": "GPLv3",
   "scripts": {
     "build": "babel src --out-dir dist",
-    "lint": "eslint --ignore-path .gitignore .",
+    "lint": "eslint --ignore-path .gitignore --ext .js,.ts,.tsx .",
+    "check-types": "tsc",
     "prettier": "prettier --ignore-path .gitignore --write \"**/*.+(js|json)\"",
     "format": "npm run prettier -- --write",
     "check-format": "npm run prettier -- --list-different",
-    "validate": "npm run check-format && npm run lint && npm run build"
+    "validate": "npm run check-types && npm run check-format && npm run lint && npm run build"
   },
   "devDependencies": {
     "@babel/cli": "^7.5.5",
     "@babel/core": "^7.5.5",
     "@babel/preset-env": "^7.5.5",
+    "@typescript-eslint/eslint-plugin": "^2.0.0",
+    "@typescript-eslint/parser": "^2.0.0",
     "eslint": "^6.1.0",
     "eslint-config-prettier": "^6.0.0",
-    "prettier": "^1.18.2"
+    "prettier": "^1.18.2",
+    "typescript": "^3.5.3"
   }
 }
diff --git a/src/typescript-example.ts b/src/typescript-example.ts
@@ -0,0 +1,21 @@
+function add(a: number, b: number): number {
+  return a + b
+}
+
+interface User {
+  name: {
+    first: string
+    middle: string
+    last: string
+  }
+}
+function getFullName(user: User): string {
+  const {
+    name: {first, middle, last},
+  } = user
+  return [first, middle, last].filter(Boolean).join('')
+}
+
+add(1, 2)
+
+getFullName({name: {first: 'Joe', middle: 'Bud', last: 'Matthews'}})
diff --git a/tsconfig.json b/tsconfig.json
@@ -0,0 +1,9 @@
+{
+  "compilerOptions": {
+    // because we're compiling with Babel instead of TypeScript
+    // and we're only using TypeScript for type checking, we'll set "noEmit"
+    // to true so running type checking doesn't generate any files.
+    "noEmit": true,
+    "baseUrl": "./src"
+  }
+}
